One
more hint: Check out the ceiling.Are there mirrors?
If yes, you might be able to count cards at a table
60 feet away.Do not be obvious about it of course;
raise your eyes without tilting your head.

The
deck should be cut also flat on the table and into
just two halves. The deck should always be cut. Your
rules can perhaps allow an additional shuffle by another
player if so requested, and a cut by the player to
his right.

Discards
should not be scattered all over the table, but placed
in a neat pile to the left of the current dealer.
No one should be permitted to "play around"
with the discards prior to the next dealer gathering
and shuffling the cards. If two decks are in play,
the second deck should be shuffled by the previous
dealer, rather than the next dealer.

If two
or three players always seem to take the same positions
relative to each other, you might consider taking
action to randomize the seating.

Educate
your players how to protect their hands (conceal their
cards from their neighbor's glance). If you know that
someone regularly exposes his cards, tell him about
it. You'll be doing him a favor, and in the long run,
helping the integrity of your game.